judgment on my credit

there is a judgment on on my credit from 2006, I am un aware of what it is actually for... I have called the creditor on the TU credit report (the only one this shows up on) they can not locate anything in their system attached to my name or any of my alias' (nick names). I even tried to give them my business name and the reference number on the TU report. The CS representative tried to locate me in the system for a good 10 minutes, and finally gave up. I mailed a letter of dispute to TU today, to have it investigated.... What else can be done? We are trying to purchase a second home and did not know this was there until denied. Both myself and my spouse have very good credit, low debt ratio, and this is hindering us. Please give advice on how to get this taken care of...